Chitosan/Polyvinyl Alcohol Based Blend Film Containing Tangerine Peel Carbon Dots: Properties, Antioxidant and Antibacterial Activities

Active packaging has become increasingly popular to meet the consumer demand associated with the quality and safety assurance. In addition, active packaging based on biodegradable materials with the selected active compounds can be environmental-friendly, unlike plastic packaging. Chitosan/polyvinyl alcohol (C/P) films containing tangerine peel carbon dots (TP-CDs) as an active packaging was prepared and characterized. TP-CDs were synthesized using hydrothermal method and incorporated into C/P blend film forming solution at varying levels (0–5%, w/w). Mechanical properties of resulting C/P blend films were markedly enhanced with the addition of 1 and 3% TP-CDs. Water vapor barrier property of resulting blend films was slightly reduced due to hydrophilic nature of TP-CDs. TP-CDs with yellow color affected the color of films differently, depending on the levels of TP-CDs incorporated. FTIR result revealed the characteristics peaks of C/P blend films. Blend films containing TP-CDs showed excellent UV blocking ability. They also had high antioxidant effect as assayed by radical scavenging activities (ABTS and DPPH), ferric reducing antioxidant power and metal chelating activity. Thermal stability of C/P blend films was slightly enhanced after the addition of TP-CDs. The inclusion of TP-CDs in C/P blend films could inhibit the growth of selected microorganisms (L. monocytogenes and E. coli). TP-CDs added C/P blend films could therefore serve as an active food packaging, especially for prolonging the shelf life and maintaining the quality of food products prone to lipid oxidation.